I didn't see anything rude with what she said.
"you should always feed F/T" is a blanket statement. many of use here feed live, the way nature intended. and if done correctly there is no issues with it. ive been feeding live with my BP and have with my snakes before it. no issues. if your an irresponsible BP owner live could be an issue. but under the proper conditions its quick, efficient and the snake gets to eat. I always say feed what works. either way is good. if done correctly.